1. Field of the Invention
The present invention relates to an improvement in an internal combustion engine for a vehicle that is provided with a torque converter.
2. Description of Background Art
As an internal combustion engine with torque converter is disclosed in Japanese Utility Model Laid-open No. Sho 54-12227. This internal combustion engine includes a torque converter for which an oil hydraulic multiple disk clutch for connection and disconnection of creep is auxiliarily and coaxially provided is fitted to a transmission shaft. An oil hydraulic clutch is operated by an oil branched from a line for supplying the oil to the torque converter. In addition, a structure is provided in which while the torque converter is constantly supplied with the oil, the oil to be supplied to the clutch is interrupted by a relief valve until a predetermined pressure is reached. When a pressure not less than a set pressure is reached attendantly on an increase in rotation, the hydraulic oil flows to connect the clutch, whereby a creep is generated.
In the torque converter for which the oil hydraulic clutch is auxiliarily and coaxially provided, the crankshaft is long, so that it is difficult to mount onto the engine. Where it is intended that the oil passage for the oil hydraulic clutch is used also for a passage of a lubricating oil from the crankshaft to a connecting rod needle, a high pressure for operating the oil hydraulic clutch cannot be maintained. Therefore, it is necessary to provide two systems of oil passages, namely, a high-pressure and a low-pressure oil passage in the crankshaft, so that hole boring for the crankshaft is complicated.